“Pounds” or “Lbs” refers to the breaking strength of the line. A line rated at 6 Lbs should not break until 6 pounds of pressure is on the line. You can catch fish larger than the “pounds” of you line. How? Set the drag on the reel to let the fish pull the line off the reel. That’s why you need Cortland Micron fly line backing on your reel.
One of the best leaders you can use…if you’re fishing top water poppers for bass…..is Spider Wire – 10lb test with 4lb diameter. The call it “diameter”…but Spider Wire is actually flat braided line. Provides a very soft landing…and because it is so strong…it will cut its way out of lily pads with just a few stiff pulls.